The present invention pertains to cryptographic communications and methods, to provide secure communication over a communications channel and to store data securely on a computing system. With the advent of computer technology and networking methods in information technology, information is made available within no time across the globe. There are various information intensive businesses that have developed and have thrived on information technology.
Communication of right information at a fast rate is highly necessary for various business fields, Banking, Electronic Mails, Data Processing and Strategic Consultancy just to name a few. Secure electronic communication is centric to almost all business forms and business units existing in this age of Information technology. While the information flow through the existing electronic communications channel is becoming faster by the day, this data is susceptible to monitoring by electronic eavesdroppers. Furthermore, issues like authentication of the source of electronic data sent over a communications channel and its verification also need to be addressed to control potential forgery of electronic signatures which can have adverse effects on transactions such as a bank draft or securities deposit wherein the signature has to be verified to ensure that the document has come from the assigned signatory and is not a fake. This highlights the need of having a secure communications channel that can provide security to the communicated data from electronic eavesdroppers as well as act as the true authentication for electronic signatures on transaction documents.
There have been cryptographic systems for secure transmission, authentication and verification of sent electronic data over a communications channel but each of them applied till date has had certain shortcomings. There have been asymmetric as well as symmetric encryption systems. All these cryptographic encoding and decoding methods ensure some degree of protection, privacy.
Symmetric encryption uses algorithms where the same keyset is used for both the encryption as well as the decryption process. The key generated must be kept secret, and is shared by the message sender and recipient. For example, a password used in a Microsoft Word document uses symmetric encryption techniques where the password used to encrypt and decrypt the file is the same and is used to secure the file from eves droppers. The person encrypting the file with a password must inform the receiver of the password, either physically or through any other means, in order for the receiver to be able to decrypt the file.
Symmetric key encryptions can be divided into stream ciphers and block ciphers. Stream ciphers encrypt the bits of the message one at a time, and block ciphers take a number of bits and encrypt them as a single unit. Typically, blocks of 64 bits are used. Symmetric-key algorithms are generally much faster to execute than asymmetric encryption algorithms. However, symmetric-key algorithms do have certain pitfalls. One being the requirement of a shared secret key with one copy at the sender and receivers end. Since keys are subject to discovery by a cryptographic adversary, they need to be changed often and kept secure during distribution and service. An alternative to this is the use of asymmetric encryption to encrypt data or to transfer the password and then carry out symmetric encryption.
One of the first cryptographic communications method to be used were the data encryption standards tools adopted by the National Bureau of Standards, Federal Register, Mar. 17, 1975, Volume 40, No. 52 and Aug. 1, 1975, Vol. 40, No. 149.
A cryptographic communications channel normally comprises of an encryption system and a decryption system coupled to the communications channel. The message is encrypted using the encryption system at one end of the communications channel and sending it across the communication channel where it is decoded by the decryption channel at the other end of the channel. For digital systems, the message is defined to be a digital message represented by numerical characters, these characters, generally being the Binary notation characters of 0 and 1. The cryptographic systems in use essentially highlight the use of an encoding key or operator, K, on the digital message that is to be encoded, M, and encode the message M onto the encoded version E, where, K and E are also digital sequences of numerical characters, represented in the same notation as M. Thus, the encrypting device takes as input, M and K, and then operates on M using K and encrypts it into E.
The decrypting device, on the other hand takes E and the decrypting key or operator K′ as the input, operates on E using K′ and decrypt it into the deciphered text M′. Where, K′ and M′ are also digital sequences of numerical characters, represented in the same notation as M. Here, the digital sequence of the encrypting and decrypting keys, or operators i.e. K and K′ are so chosen that M′=M.
In the available literature on cryptographic systems, for instance, Public key cryptosystems as described by Diffie and Hellman in “New directions in cryptography”, IEEE Transactions on Information Theory (November 1976), much is talked about the use of Public and private keys to encipher the data to be communicated and also to decipher it. The methodology of cryptography presented in the above-cited literature by Diffie and Hellman emphasizes on the use of a public key (KP) to encrypt the message M. To decrypt the message from the cipher-text E; the private key KPr is used.
The public and the private keys are so selected that M′=M. The public key (KP) is available on the public file system of the user, whereas the private key (KPr) remains with the user. Whenever, a user B has to send an encrypted message to user A, the message M is encrypted using the public key of user A. User A then decrypts the encrypted message using the private key which is known only to user A. This method is further employed to act as the authorization on electronic signatures. To successfully implement the Diffie and Hellman method described above, it is absolutely essential to make a judicious selection of the private key, as this selection would determine the vulnerability of the encrypted message to eavesdroppers. The selected key should be computationally difficult to compute. However, there would always exist brute force methods to compute the private key of a user, one such method being listing of all possible messages M until one such M where KP(M)=E and then KPr can be computed using KPr (E)=M.
The RSA patent, U.S. Pat. No. 4,405,829, has employed a scheme to generate the private key for the user based on prime number factorization to make the computation of the private key by eavesdroppers computationally much difficult (computationally expensive process). The RSA method of encrypting and decrypting employs the same public and private key concepts as mentioned in the Diffie and Hellman system to encrypt and decrypt a message. The operations performed onto the message to encrypt the message into a cipher-text involve the representation of the message as a number equivalent wherein the number equivalent is a non-negative number less than a composite number n which has two prime number factors i.e. n=p·q, where p and q are prime numbers.
These existing systems however, do not offer full security from eavesdroppers, as although they involve the computation of the private key required to decipher an encrypted message, which is extremely difficult as it involves the computation of prime numbers at different stages and as the size of the number, whose prime factors are to be found, increases, the process becomes more and more expensive. However, with the advent of supercomputers and high speed computing, finding prime number algorithms can be implemented much faster and hence the encrypted messages can be decrypted, obstructed and forged by eavesdroppers. More so, these encryption-decryption modules involve a public key which is available to all, the task is to generate the private key which is only with the user.
Also, as per Shannon's theory of perfect secrecy or unknown condition, in order for a cipher to be unbreakable, the keyset required to encipher it should be unique for every message and the length of the keyset should be greater than or equal to the length of the message to be communicated. No method of encrypted communication can be totally secure until it employs the above-mentioned scheme.
The proposed system and method hopes to overcome all the shortcomings of the existing technologies to provide a full-proof unbreakable symmetric key encryption. The system and method is also used to address the needs for generating random numbers and unique hash codes.